>>The following works if a computer has a network card from which you can read the SN. The easiest way I know is to generate a new GUID and take from it the network card SN.
>>
>>Of course, this number is specific to the network card, so, if the user changes the network card, your software will not work anymore. But this problem doesn't have a solution. Whatever ID you would use, the user can always change that part (or even the whole computer), so, you have to deal with this situation anyway.
>>
>>Vlad
>
>Hello Vlad
>
>Yes, i want to get any hardware SN or ID, for my software to be activated with a different key on each computer.
>I know this is a problem, but this a way to avoid local piracy.
>
>Not all computers have a network card because my clients will be 1-user systems.

In addition, it won't work if your suers change NICs, or if they legally run the software on a network. And a suffucuently dedicated individual can override the MAC address for the NIC if he knows what he's doing, since the interface to read the MAC address could be intercepted as well.